Russia Steps Up Security for Sochi Olympics

Black Sea Resort Turned Into Controlled Security Zone

MOSCOW—Russia cast one of the most extensive security nets in Olympic history over the city of Sochi on Tuesday, activating restrictions on the Black Sea resort a month before the start of the Winter Games.

The sweeping safety regime restricts access to sensitive areas and puts thousands of officers on "combat alert," a measure stemming from an Olympic security order that Russian President Vladimir Putin issued last year....